NORTHEAST OKLAHOMA — Two years ago, community and state officials gathered in a field near Vinita, Okla., to reveal with considerable fanfare plans to build a “world-class theme park” that would attract visitors from across the U.S. and employ thousands of people. Today, the wind still blows across empty northeast Oklahoma fields and the dream of an attraction bigger than Disney World has evaporated. This week, Gene Bicknell, the principal financial backer of the project, filed a lawsuit alleging that three men “coerced him into sinking more than $60 million into the design and construction of the American Heartland Theme Park.” The lawsuit, filed in the U.S. District Court for the Northern District of Oklahoma, alleges that over a period of years, Richard M. Silanskas Jr. and Larry K. Wilhite, assisted by Stephen “Steve” Hedrick, “orchestrated a campaign of deception” to defraud Bicknell, who is 91.